Liquid Crystal Technique for Identifying Locations of Transistor Leakage
Original Publication Date: 1978-Apr-01
Included in the Prior Art Database: 2005-Feb-20
Liquid crystals have been used for some time for digital displays and locating oxide defects but the application of this material for leakage limited yield (LLY) characterization is unique. Liquid crystal fluid contains long molecules which tend, under normal conditions, to line up and transmit light. If an electrical potential is present, it disturbs the dipoles on each molecule. This results in turbulence which can be seen in the liquid crystal, and the effect is known as dynamic scattering. This turbulence causes a change of refractive index and can therefore be seen clearly through the microscope.